US2526289A - Refractory lined container - Google Patents

Description

' formly throughout their abutting surfaces.

Patented Oct. 17,- 1950 REFRACTORY LINED CONTAINER Griffith G. Smith, Ligonier, Pa., assignor to Carnegie-Illinois Steel Corporation, a corporation of New Jersey Application June 25, 1947, Serial No. 757,004

1 Claim.

This invention relates to an improved container for molten materials with a high melting point, such as ferrous metals, said container having an inner lining of refractory material.

The invention has among its objects the pro- .vision of a container of the above character, the inner lining of which or at least a substantial part of such inner lining, is composed of refractory shapes which expand or bloat upon reheating at a predetermined temperature for a predetermined minimum time; The refractory shapes making up such inner lining are so made that they display difierent amounts of such expansion in diiferent directions, and are so laid up in the container that the dimensions along which the greater expansion takes place are so oriented with respect to the container that the spaces between shapes become substantially filled and the lining becomes substantially monolithic upon reheating the shapes after lining the container.

This and further objects of the invention will be more readily apparent in the following description.

Refractory linings for containers adapted to hold molten highmelting point metals,'such as ferrous metals, as for instance ladles, mixtures, and the like, should ideally have inner linings totally impervious to the molten material-which they contain. To be capable of long service life such linings should at least prevent any substantial leakage of the molten material such as metal into the crevices between the separate refractor'y shapes of which the lining, as a practical necessity, is formed. When such leakage occurs, removal of skulls, that is, the solidified material on the bottom of the container, tends to damage the lining'since the thin fins of solidified material between refractory shapes pull out portions of the lining so that they are removed with the skull. Containers are of necessity curved at least in some portions of their walls, and it is impractical to form the refractory shapes to line such curved portions of different cross-sections to make the adjacent shapes contact uni- The problem of securing an inner lining for such containers which is liquid tight, with respect to the high melting point liquid contained therein, particularly at the curved portions of the container, has been heretofore especially difllcult.

In producing refractory shapes for making the lining in accordance with the present invention,

,refractory shapes of expanding or bloating refractory are formed by the extrusion through a die of a column of such refractory, such column then being cut-into suitable lengths, as by a conventional wire cutter. The shapes thus made are so oriented with respect to the extrusion die and to the cutter that the dimensions along which maximum expansions are desired are those normal to surfaces which have been in contact with the shape defining surfaces of the extrusion die, the dimensions along which a minimum expansion is desired being that normal to cut surfaces. The refractory shapes so formed are then fired at the usual temperatures and for the usual time, after which they are laid up in the container to form the inner or working lining thereof. Dimensions of the shapes along which maximum expansion upon reheating takes place are laid parallel to those dimensions of the container shell which require such greater expansion to enable the lining upon reheating to form a substantially monolithic lining. It has, for example, been found preferable to employ the shapes so that their dimensions of maximumcxpansion are laid up parallel to the direction in which the greatest curvature of the shell lies.

The invention will be more readily understood by reference to the accompanying drawings in which:

Figure 1 is a view in axial vertical section through a molten metal containing ladle, the inner lining of which is formed in accordance with the present invention; and

Figure 2 is a schematic view in perspective of a portion of the apparatus employed to form the brick in accordance with the present invention. The typical bottom-pour ladle shown in Figure 1, designated generally by the reference character 2, has an outer metal shell 4, such'shell being made up of portion 4 which defines the side walls of the ladle and the portion 6 which forms the bottom of the ladle. The side wall defining portion 4 is curved in horizontal section throughout all or a major portion of its extent, such ladle most usually having a circular cross-section. The bottom 6 is usually formed flat, sloping somewhat in a direction downwardly toward the pouring spout, which is shown at the lower right-hand corner of the ladle in Figure 1.

The ladle is provided with a refractory lining, the portion of the lining on the bottom being designated generally by the reference character 8, that on the lower side walls being designated l0 and that on the upper side walls being designated l2. The bottom refractory lining 8 is made up of a plurality of layers of conventionally formed flrebricks, shown at M, and a top inner layer l6 of refractory shapes made in accord-v ance with the present invention, such top layer forming the so-called working bottom of the ladle. The individual shapes of bricks making up such top layer Ii are designated I8.

The side walls are provided with an outer backing layer of refractory, such as bricks 26 formed of conventional firebrick, and the lower portions of the side walls are provided with an inner lining formed of bricks made in accordance with the invention. The bricks making up the lining in the lower portion of the side walls are of the same type as those employed in the working bottom and are consequently likewise denoted by the character 18.

The bricks l8 making up the working bottom of the ladle are of the customary rectangular parallelopiped shape, in which the dimension designated L, the length, is greater than that designated W, the width, which in turn is greater than that designated T, the thickness. Brick I8 may conveniently be of conventional brick size, that is, 8% by 4 by 2% inches. The bricks in the working bottom, as will be apparent from Figure 1, are all laid up in the same direction so that their dimensions W lie vertically and their lengths L are parallel. Such bricks I8, as will be apparent hereinafter, are so formed that upon refiring the expansion along the dimension of their thickness'materially exceeds that along the dimension of their length, both such expansions in turn being substantially greater than that along the width of the brick. Although the problem of securing relatively tight joints between the shapes on the fiat bottom is not so difficult as that in curved portions of the container, it will be apparent that the laying of the bricks in the bottom so that the two dimensions of maximum expansion lie parallel to the shell insures the substantial filling of crevices between such bricks when they expand upon refiring. The bricks may be laid up dry, particularlyin the working bottom, but they may if desired be laid up with thin layers of fire clay between them.

As stated, the bricks employed as the inner lining of the lower portion of the side walls are the same as those employed in the working bottom. In this instance, however, as will be clear from Figure 1, they are laid up so that the length L lies vertical, the thickness T lies in a horizontal direction, and the width W lies substantially normal to the ladle shell. It will be seen that, by disposing the bricks with their dimension of greatest expansion parallel to the dimension of greatest curvature of the ladle shell, the bricks upon reheating expand preferentially in such manner as effectively to fill the crevices between the vertically abutting surfaces of adjacent bricks, between which there must of necessity, when the bricks are laid, be a crevice, particularly at the rear portions of the bricks remote from the material containing space within the ladle. Such crevices may be filled initially, if desired, as above indicated, with fire clay applied when the bricks are laid.

Refractory fire clay bricks of the expanding or bloating type to be used in making brick 18 are of the high silica type made from fire clays of which the following composition range, given in per cent by weight, is typical:

Per cent Si02 60.00-70.00 Fezm 2.00- 5.00 TiOz .50- 1.00 CaO .40- 1.00 MgO .40- 1.00 Alkalies 2.50- 4.00

'Refractory bricks made from the above com position have a. refractoriness of pyrometrical cone equivalent (P. C. E.) of from 16 to 23, inclusive, (2669 to 2876 F.) and a, permanent linear expansion of at least approximately 10 per cent along all dimensions when reheated at 2350 F. for five hours. Linings formed of such bricks when laid in fire clay are customarily dried by burners placed within the ladle after the lining is laid, following which the ladle is put into service. the heating from the molten charge being relied upon to refire the bricks composing the inner lining and thus to produce their expansion to seal the lining joints. When the lining bricks are laid up in fire clay, the fire clay at the joints temporarily seals the Joints until the bricks expand sufficiently to do so.

Bricks 18 are formed in apparatus such as that indicated in Figure 2, in which reference character 36 indicates a portion of an extrusion press having a die orifice 38. The column of fire clay 40 issues from the orifice 38 and is delivered on to a conveyor table 42 where it is cut into lengths by a conventional wirecutter, schematically shown as composed of the two side supports and spacers 44 and the cutting wires 46. In forming the bricks 18, the column 40 is of such dimensions and wires 46 are so spaced that the vertical dimension, of the column is the same as the thickness T of the bricks, the width of the column is the same as the length L of the bricks, and the distance between adjacent cutting wires 45 determines the width W of the bricks.

It has been found that the greater expansions of fire-brick shapes formed in the manner shown in Figure 2 take place along those dimensions which are normal to the surfaces which have been in contact with the shape defining surfaces of the extrusion die, and that the least expansion takes place along the dimension which is normal to those faces, which have been wire cut. As an example, brick l8. formed of a fire clay within the composition range given above, has the following characteristics:

P. c. E. (cone) (2'768 F.) 19

Absorption 6.3 Apparent porosity 14.0

Bulk density (oz. cu. in.) 1.30 Permanent linear change on reheat for 5 hrs. at 2350 F.:

Per cent expansion Length 15.5 Width 9.? Thickness 23.7

Having thus fully disclosed the improved container for molten high melting point metals of my invention, I desire to claim as new the following.

I claim:

A ladle for molten material having a high melting point, such as ferrous metals, which comprises anouter shell having a bottom wall and sidewalls, the sidewalls being substantially straight vertically and curved horizontally, and a refractory lining in said shell of fire clay bricks, the exposed bricks of said lining on the bottom wall and on the lower section of the sidewalls having a refractoriness of pyrometric cone equivalent of 16 to 23 inclusive and being of the bloating type having significant permanent linear expansion in all directions, said exposed bricks being of rectangular parallelepiped shape and having appreciably greater width than thickness and appreciably greater length than width, the pera manent expansion being appreciably greater in the directions of length and thickness than in the direction of width, said exposed bricks on said bottom wall being laid with their length and thickness directions parallel to said bottom wall and their width direction normal to said bottom wall, and said exposed bricks on the lower section of said sidewalls being laid with theirlength and thickness directions parallel to the sidewall which they overlie and their width direction normal to the sidewall which they overlie, so that the exposed bricks on said bottom wall and on the lower section of said sidewalls permanently expand parallel to their respective walls sufliciently to seal the crevices between bricks.

GRIFFITH G. SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Numzer Name Date 1,616,074 Astrom Feb. 1, 1927 1,870,220 Astrom Aug. 9, 1932 1,889,426 Stout Nov. 29, 1932 1,928,813 De Fries Oct. 3, 1933 2,219,606 Van Schoick Oct. 29, 1940 2,223,617 Johnston Dec. 3. i940

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